Cutting is off

[john_hartman]

So I measured a few peices cut on the bot using partworks that where short by 1/16" in the x axis. The y axis is cutting to the exact specified measurement. These files where Turbo cad files saved as DXF then opened for toolpathing in partworks. Does anyone have an idea what could be going here?

[ken_rychlik]

probably something to do with the dxf from turbo cad

Why don't you just draw it in Part works?

You may check your unit values,... type VU with the software open.

The values for x and y normally are the same. It would be good to double check it though.

[andyb]

I agree with Kenneth. Draw a couple of squares, circles and triangles in Partworks. Cut and measure them. I had a customer send me a DXF file that he created in a lesser known CAD program. All the measurement were off by an 1/8" when I got them. We went back and forward until he imported the DXF back into the CAD program and it was off 1/8" there too.

Andy B.

[john_hartman]

Thanks guys.

Ken- I will check the unit values. I can draw a lot faster in turbo cad and part works can be time consuming when it comes to trimming lines.

Andy- What is the difference between dxf and eps? Is there a rule of when to use one over an another? Do you know what your client did to inprove the file? Did he just enlarge the drawing by an 1/8"? Is it not strange that the difference is just in one direction?

[adrianm]

What version of PartWorks are you using?

The latest has the scissors tool which makes trimming vectors easier than any other package I've used.

I always ask for EPS files whenever possible. I seem to have a lot less hassle with them compared to DXF files and anything with curves seems to be a lot nicer in EPS.

[dana_swift]

This does not sound like a partworks problem, although it could be. If the dimensions of the imported drawing are wrong, then I retract the previous statement.

If the CUT size is wrong, it is more likely unit values are wrong in the X axis. Check there first, especially if Y axis is within tolerance.

D

[Brady Watson]

It could also be that you are cutting the parts too quickly causing the tool to deflect.

Try cutting a square using CLIMB direction. Then cut the same size CONVENTIONAL direction.

See if there is a difference in size.

-B

[john_hartman]

I checked the unit values and they are identical. I have not yet tried cutting a square in climb/conventional. I am using a Centurion .25 compression bit @ 3ips, 10k rpm, .375 cut per pass in maple ply. I think I can cut faster than this but have avoided it primary to prevent any deflection. Assuming that I fall short with these tests what else can I look for?

[andyb]

John,
My customer updated the program. There was a bug in the export filter.

Andy B.

[Gary Campbell]

Andy....
Thanks for posting your findings. Many do not. This allows others in the future to have a possible solution to a similar problem.

[john_hartman]

Andy- Am I missing a link or something? Based on Gary's comment it sound like there is something that may help me? thanks

[ken_rychlik]

I think gary misunderstood who had fixed their problem.

[andyb]

Gary,
Been doing IT support for 25+ years. First thing to always look for is that they are running the latest version of the software. You would be surprised at the amount of problems and headaches that can resolve. ;)

John,
The problem was not in Partswork or Aspire in my case. It was in the 3rd party CAD program my customer was using. It was their export addin that was having a problem. Not sure which CAD program. What I'm saying is for whatever version of the CAD program (or any program for that matter) you are using make sure that you are running the latest updates for the version. My customer was several updates behind. Once he downloaded the updates and got current, problem solved. He said it fixed other little problems he was having too.

Andy B.

[Gary Campbell]

John...
Kenneth is right. I got twisted up. Sorry about the mixup.

Looks like we are waiting to see the results of your climb/conventional cutting results. The next thing to check would be the actual sizes of the imported vectors in PWks. Select the rectangle and hit [T] to see if the size is what you believe you imported.

[john_hartman]

I am using a pretty recent version of Turbo CAD; v.10. I'm not sure I understand how the version would affect how program translates infomation.

Gary- What are you saying here: "Select the rectangle and hit [T] to see if the size is what you believe you imported."

If I draw a rectangle say 24x36 in Turbo cad, save it as an eps file, then open it in PW, then that exact size is displayed when I click on the that rectangle.

[Gary Campbell]

John...
To clarify.... as you sounded like you talking of the hypothetical. Was the rectangle that caused the erroneous cuts the correct size? If so then your problem is mechanical. Since you say that the problem is only in the X, then the climb/conv test that brady suggests will sort that out. You may want to double check your X pinion grub screws and make sure the motor is snug up into the rack.

[ken_rychlik]

John,

I still don't understand why you want to draw it in turbo cad to start with.

Drawing is easy in partworks.

Anytime you transfer information from one place to another, there is always the chance of something going wrong.

Anyway....

I had one other thought. If the pinion set screws on the x motors were not tight, it could cause the problem you describe. It would skew the x distance and not the y.

If it really is the machine not running the correct distance for a given command, you can adjust the unit value for x to correct it. I would do this as a LAST RESORT though.

Do a simple ratio.... example

you say move x 90 and it moved 89

PRETEND the unit value is 2200

your math would be 2200*90/89 2224.719101 should fix it under this situation. "I think" :rolleyes:

[john_hartman]

Yes- the sizes seem to translating properly from t-cad to eps to PW.

This "grub" screw is the one that locks the pinion on to the motor arbor with the flat indent; correct? Your suggesting that the pinion could be just loose enough to not match same number of rotations as the motor...and/or the pinion and rack teeth are not meshed properly?

[Gary Campbell]

John...
Yes on the grub screw.

If the pinion gear is loose to the shaft, or the gear is not tight to the rack, that slack will give the undersize in X results you reported. Also the rollers on the bottom of the Y car, if not adjusted properly, could do the same.

[john_hartman]

Thanks Gary- I'm thinking this may be the cause of my problems. I have noticed a "clicking" as the y car moves from 49" back to 0,0. I will investigate this further..:)

[cedarheaven]

I don't mean to step in on a thread but I have a question concerning the ShopBot Buddy 32....
Is there a website that individuals who have previously spent time creating ?? Is there a place one could purchase files & plans for sale?